What is Asthma?
Asthma is a chronic inflammatory condition that causes recurrent episodes of airway narrowing (bronchoconstriction), excess mucus production and thickening of the airway walls due to the underlying bronchial hyper-responsiveness, making it harder to breathe.
Asthma can affect all ages but usually starts in childhood and only rarely presents with a new-onset in adults. Most cases of asthma diagnosed in adults usually had started in childhood whether or not unbeknownst to the individual. In many cases, childhood asthma subsides in adolescence, however it can recur in adulthood.
In Europe, 30 million children and adults less than 45 years old have asthma. According to the epidemiological research study conducted by the Asthma team at the Hellenic Thoracic Society, the prevalence of asthma in Greece is 8.6%, in other words, approximately 900,000 children and adults have asthma.
Causes
There is no known cause for asthma. The inflammatory process of the airways that is associated with asthma, depends on the interaction between the genetic predisposition of susceptible individuals and exposure to certain environmental factors such as pollution and Western lifestyle (ERS).
Asthma is characterised by hyper-responsiveness, an exaggerated reaction of the airways when exposed to irritative factors and triggers.
Symptoms
Asthma presents with episodic respiratory symptoms (flare-ups or attacks) characterized by one or more of the following:
- Shortness of breath
- Chest tightness/pain
- Coughing
- Wheezing (a whistle or wheeze sound when exhaling)
- Difficulty sleeping from coughing/wheeze or shortness of breath
- Intense cough or wheezing made worse by a viral cold or flu
Asthma is known to manifest by attacks of symptoms that can remit or relapse and are usually provoked by certain triggers. Symptoms vary in combination, frequency, severity and time course. Each person experiences asthma differently and it is therefore important to consult often with their physician.
Triggers
Often asthma attacks can be brought on by:
- Exercise (exercise-induced asthma)
- Occupationally-related irritants like chemical fumes, gases or dust (occupational asthma)
- Allergens such as pollen, pet dander, mold or cockroach waste
- Cold air
- Stress
- Viral respiratory infections i.e. the seasonal flu
- Sulfites and preservatives
- Gastro-oesophageal Reflux Disease (GERD)
Diagnosis
There is no specific test for diagnosis, however, the following criteria are used to aid in diagnosis of asthma:
- Indicative medical history (i.e. episodic symptoms, flare ups)
- Physical examination (i.e. wheezing)
- Obstructive pattern (airflow limitation) on spirometry
Laboratory Evaluation
Lung Function Tests:
- Spirometry: determines and measures the degree of airway obstruction
- Bronchodilator response: Spirometry pre- and post- bronchodilator administration evaluates the reversibility of the obstruction
- Broncho-provocation: an asthma trigger, such as inhaled metacholine, administered to individuals with normal spirometry, can reveal the characteristic bronchoconstriction of asthma.
- Measurement of Exhaled nitric oxide: the concentration of NO in the exhaled breath increases in cases of eosinophilic inflammation of the airways.
Blood Tests: are used as an aid to diagnosis, they are not specific.
- Complete Blood Count, eosinophils count, total serum IgE, allergen specific IgE (ELISA, RAST)
Allergy Skin Tests: do not diagnose asthma, but help reveal the triggers
Prevention
The aim is to:
- Avoid exposure to known triggers and environmental pollution
- Avoid smoking and exposure to passive smoke
- Monitoring of symptoms and lung function
- Ensure adherence to treatment
- Ensuring proper treatment during pregnancy: all pregnant women should be asked about asthma and advised about appropriate treatment during their pregnancy
Treatment
Aims to:
- Reduce frequency, duration and severity of attacks
- Preserve a normal lung function
- Minimise risk and avoid or reduce permanent adverse outcomes
- Reduce hospital admissions
Treatment is adjusted for the individual patient once his asthma has been evaluated in regards to severity, frequency, precipitating factors and symptom control and according to the international guidelines. (GINA)
Medication includes one or more of the following:
- Combination of long-acting bronchodilators and corticosteroid inhalers
- Oral corticosteroids
- Oral theophylline,
- Anti IgE therapy
- Monoclonal antibodies
The attending physician will adjust the treatment, step medication up or down accordingly and help design an action plan for the individual patient. (GINA)
References
European Respiratory Society. “Adult Asthma.” In European Lung White Book, https://www.erswhitebook.org/chapters/adult-asthma/ (April 19, 2019).
For the Greek version of this article, click here.